Just skimmed through George Eldon Ladd’s The Gospel of the Kingdom. I have been edified before by his New Testament Theology and Blessed Hope. I think I can safely recommend this as a book all Christians sitting our pews would benefit by reading. Ladd himself makes it clear that this book is proclamation and not detailed argumentation, so it is clear and easy to read. It is a good introduction.
Ladd’s theology is indebted to German theologian Oscar Cullman (see his Christ and Time), but a reading of Ladd is a great cure for all kinds of infections like:
*Gospel as getting to Heaven
*The Left Behind Series